In several documents e.g. No. EP-A1-005 129, No. GB-A-20 38 825, U.S. Pat. No. 4,327,102, U.S. Pat. No. 4,182,766 and No. EP-A-80 602 heterocyclic compounds active as inhibitors of gastric acid secretion have been described. Two of these documents namely No. EP-A1-1 0 005 129 and No. EP-A-80 602 describe substituted [[(2-pyridinyl)-methyl]-sulfinyl]-1H-benzimidazoles and also in U.S. Pat. No. 4,097,603 such compounds and their thioanalogoues have been described. According to the last mentioned document the compounds are known as cytoprotective agents. Because of their antisecretory effect the known compounds may be used in the treatment of gastrointestinal diseases, e.g. peptic ulcer.